1. Field of the Invention
The present invention is directed to a steam engine and, more particularly, to a heat regenerative engine which uses water as the working fluid, as well as the lubricant, and wherein the engine is highly efficient, environmentally friendly and adapted for multi-fuel use.
2. Discussion of the Related Art
Environmental concerns have prompted costly, complex technological proposals in engine design. For instance, fuel cell technology provides the benefit of running on clean burning hydrogen. However, the expense and size of fuel cell engines, as well as the cost of creating, storing, and delivering fuel grade hydrogen disproportionately offsets the environmental benefits. As a further example, clean running electric vehicles are limited to very short ranges, and must be regularly recharged by electricity generated from coal, diesel or nuclear fueled power plants. And, while gas turbines are clean, they operate at constant speed. In small sizes, gas turbines are costly to build, run and overhaul. Diesel and gas internal combustion engines are efficient, lightweight and relatively inexpensive to manufacture, but they produce a significant level of pollutants that are hazardous to the environment and the health of the general population and are fuel specific.
The original Rankin Cycle Steam Engine was invented by James Watt over 150 years ago. Present day Rankin Cycle Steam Engines use tubes to carry super heated steam to the engine and, thereafter, to a condenser. The single tubes used to pipe super heated steam to the engine have a significant exposed surface area, which limits pressure and temperature levels. The less desirable lower pressures and temperatures, at which water can easily change state between liquid and gas, requires a complicated control system. While Steam Engines are generally bulky and inefficient, they tend to be environmentally clean. Steam Engines have varied efficiency levels ranging from 5% on older model steam trains to as much as 45% in modern power plants. In contrast, two-stroke internal combustion engines operate at approximately 17% efficiency, while four-stroke internal combustion engines provide efficiency up to approximately 25%. Diesel combustion engines, on the other hand, provide as much as 35% engine efficiency.